Modern vehicles, such as aircraft, often include head-up displays (HUDs) that project various symbols and information onto a transparent display, or image combiner, through which a user (e.g., the pilot) may simultaneously view the exterior. Traditional HUDs incorporate fixed image combiners located above the instrument panel on the windshield of the aircraft, or directly between the windshield and the pilot's head.
More recently, “head-mounted” HUDs have been developed that include near-to-eye (NTE) display devices. Depending upon the particular end-use environment, these NTE display devices may be coupled to a helmet or headset of viewer, and thus move with the changing position and angular orientation of the viewer's head. This advantageously allows the displayed information to be visible to the viewer regardless of the position or orientation of viewer's head. In many implementations, the NTE display devices, when operating, will generate a virtual image that may appear to be rendered on a remotely located surface within the viewer's field of view. For example, in the context of a vehicle, the virtual image may appear to the viewer to be rendered on the vehicle windshield, floating a distance (e.g., 20 feet) beyond the windshield at a fixed position in space, or floating at infinity but fixed to the environment.
One of the potential drawbacks associated with NTE devices is that the virtual image may fail to “stick” to the remotely located surface during movements of the viewer's head, resulting in image blur or the display of so-called image artifacts. This phenomenon may occur even during relatively low-speed head movements. When NTE devices are implemented in aircraft, the devices are often used during turbulent flight conditions. For example, while landing the aircraft under stormy conditions. During these flight conditions, viewer head movements may be unavoidable.
Hence, there is a need for a NTE display system and method that at least reduces image blurring and/or image artifact display that may result from viewer movements. The present invention addresses at least this need.